Marking die



June 30, 1942; H. J. MUMMA 2,288,015-

MARKING DIE Filed Oct. 18, 1939 ENTOR ATTORNFY Patented June 30, 1942MARKING DIE Harold J. Mumma,

Glendale, Oalif., assignor t Ahlburg Company, Los Angeles, Calif., acorporation of Californi Application October 18, 1939, Serial No.299,985

2 Claims.

This invention relates generally to making dies or stamps for formingink impressions. More particularly it relates to a marking dieapplicable for the marking or branding of fruits such as oranges andlemons.

The conventional type of marking die makes use of raised characters,formed upon a die body or block, and which are periodically orintermittently inked by contact with inking devices such as ribbons,rolls, or pads. Such inking devices involve certain operatingdifficulties, aside from the necessary mechanism complications,particularly when the dies are utilized in automatic or semi-automaticmachines, such as machines for applying markings or brands to fruit. Itis an object of the present invention to provide a marking appliancewhich need not be inked by contact with such inking devices, and whichcan be maintained at all times in condition to apply a properimpression.

Another object of the invention is to provide a novel type of markingdie having provision whereby a supply of fluid ink is available at alltimes upon the marking surfaces of the die.

Additional objects of the invention will appear from the followingdescription in which the preferred embodiment of the invention has beenset forth in detail in conjunction with the accompanying drawing.

Referring to the drawing:

Fig. 1 is a plan view illustrating apparatus incorporating the presentinvention.

Fig. 2 is a cross-sectional view taken along the line 22 of Fig. 1.

Figs. 3 and 4 are enlarged plan details, showing the manner in which theink feeding slits are formed.

Fig. 5 is an enlarged cross-sectional detail showing the manner in whichslits are interrupted so that various portions of the die block areintegrally retained together.

Fig. 6 is a cross-sectional detail, illustrating diagrammatically themanner in which fluid ink is supplied to the slits.

Referring to the apparatus illustrated in the drawing, I have shown adie block In made of suitable metal, and having its upper face providedwith raised letters H. In place of letters it is evident that figures,insignia, or other characters, can be formed. To afiord a mounting forthis block it is shown carried by an adapter block [2, which in turn isseated upon the mounting plate l3.

Figs. 3 to 5 inclusive illustrate the novel manner in which the block I0is formed. Thus the elongated portion Ha of a raised character isinterrupted by a relatively narrow longitudinal slit I4. Such a slit canbe formed by a relatively thin saw blade, as for example a blade capableof cutting a slit of the order of 0.0075 inch wide. As indicated in Fig.3 the slit as it enters the character must commence from one edge of theblock It). In order to rigidly retain all portions of the blocktogether, without securing a stencilling effect, it is desirable to havethe slits interrupted by integral portions l6 of the block. Theseportions can be formed by cutting with the saw blade from oppositedirections, and at opposite angles whereby the slot is made continuousfor the raised character, while it is interrupted below by a wedgeshaped portion of the body.

After the slits have been formed in the manner described suitable solderor like filling medium is applied to fill the ends of the slitsextending beyond the contours of the characters. Thus in Fig. 4 the slitportion i ta extending beyond the end of the character portion Ila, isshown filled with solder or other suitable medium so that the open slitterminates within the contour of the raised character.

In using the die block described above the mounting is adapted to supplyfluid ink to the lower side of the block, whereby the slits aremaintained filled with the ink at all times. In this connection'it isdesirable to utilize an ink which is solid at normal temperatures,together with provision for maintaining the ink together with themarking die and associated parts, at an elevated temperature. Thus thespace I7 below the die l0 and adapter I 2, forms a reservoir for ink,which communicates with a duct or passage l8, leading to an inkcontainer l9. An electrical heating element 2! is shown in contact withthe lower side of the mounting plate l3, and in order to control thesupply of current to this element and thus maintain a relativelyconstant elevated temperature, I have indicated a suitable thermostaticswitch 22. By means of this arrangement the entire assembly can bemaintained at an elevated temperature, as for example a temperature ofthe order of degrees F.

The ink utilized should be one which is relatively fluid at the elevatedtemperature of operation. A suitable ink may be one containing normallysolid waxes, such as beeswax. Care should be taken so that the amount ofink in the container I9 is not sufiicient to establish a hydraulic headsufficient to cause discharge of ink through the die block. In normaloperation fluid ink fills duct 18 and the space H, and also completelyfills the slits 14, to a level substantially coincident with the upperface of the raised characters. This is indicated diagrammatically inFig. 6. Now if an object such as an article of fruit 23 is impressedupon the characters of the die, as for example by rolling the fruit overthe marking die, the surface of the fruit will contact the ink at theupper ends or edges of the slits, with the result that the inksolidifies on the relatively cool surface of the body and a good inkimpression will be placed upon the surface of the fruit. The ink appearsto maintain itself at the upper ends of the slits for optimum contactwith a surface applied to the characters, irrespective of small changesin the level of ink within the container l9. There is no marked tendencytowards smearing of the ink and the slits do not readily become clogged.

Such a marking die can be used continuously over a long period of time,and it entirely dispenses with use of additional inking devices.

I claim:

1. In a self inking marking appliance, a die block having raisedcharacters formed on its upper face, relatively narrow slits extendingthrough the block and through the characters, whereby said slitsinterrupt the outer faces of the characters and follow generally thecontouring of the characters, a mounting for the block, said mountingaffording a reservoir for ink upon the underside of the block and incommunication with said slits, said slits providing a supply of ink bycapillary action at said upper face, and means for supplying a fluid inkto said reservoir.

2. In a marking die, a die block having raised characters formed on itsupper face, a mounting for the block forming a reservoir extendingbeneath the block, a container in communication with said reservoir, thecontainer adapted to receive a quantity of normally solid fluid ink,relatively narrow slits formed through the block and the raisedcharacters, the slits communicating with the faces of the characters andfollowing generally the contouring of the characters, the slitsproviding a supply of ink by capillary action at said upper face, andmeans for heating the mounting together with the block and saidcontainer to an elevated temperature, to maintain the normally solid inkin fluid condition.

HAROLD J. MUMMA.

